Apparatus for testing the hardness of metals and other materials



Apr. 24, 1923.

H. MOORE ET AL APPARATUS FOR TESTING THE HARDNESS OF METALS AND OTHER MATERIALS Filed Sent. 29, 1920 Fig.2.

Fig.5.

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In l 1 V E NTORS liMao'r,

Patented Apr. 24, l l'ln trier...

APPARATUS FOR TESTING THE HARDNESS OF METALS AND OTHER MATERIALS.

Application filed September 29, 1920. Serial No. 413,655

To all whom it may concern:

Be it known that we, llnnono Moons, B. So, and RICHARD MA'rr-rnu, both subjects of the King of Great Britain and Ireland, all of the research department, Royal Arsenal, lVoolwich, in the county of Kent, England, have invented a certain new and useful Tmproved Apparatus for Testing the Hardness of Metals and Other Materials, of which the followin is a specification. 4

This invention relates to apparatus for testingthe hardness of metals or other materials of thekind in which a hardened steel ball is adapted to be pressed under a known 5 load into contact withthe material to be devise an improved form of apparatus of the above character which shall be particularly, though not solely, applicable to the determination of the hardness of very thin specimens, and the invention consists in apparatus of the type referred to comprising a weight adapted to be suspended freely on the ball for the purpose of applying the known load.

The invention consists in other details and arrangements hereinafter described or indicated.

The accompanying drawings illustrate one convenient form of apparatus in accordance with the invention.

Figure 1 is a front elevation,

Figure 2 is a plan illustrating a detail,

Figures 3 and 4; are views illustrating two modified forms of support for the test specimen.

Figure 5 is a fragmentary view showing in elevation a modified method of suspending the load, and

Figure 6 is a plan corresponding to Figure 5.

In carrying our invention into effect in one convenient manner we provide a stirrup or adapted to carry a known weight b and supported from a crosshead 0 carried on two vertical columns d and provided with a screw 6 and hand wheel 7 or other suitable means for slowly raising or lowering the stirrup.

In order that there may be no tendency upon the part of the stirrup to rotate due to the rotation of the hand wheel relatively to the screw we provide two vertical. guide rods 9 and connected to a cross member secured to the screw 6 passing through. the block 9 and oscillation of the stirrup is prevented by adopting a suitable method of suspension for the stirrup.

In the form shown in Figure 1 this is accomplished by mounting the stirrup by means of an upper cross member it upon threetriangularly spaced and preferably equidistant steel balls '5 carried on a lower horizontal member 70 secured to or carried by the vertical rods 9.

An alternative method of suspension is shown in Figures 5 and 6 wherein one suspension ball 2' only may be used or in a further modification a hemispherical nose seating in a circular recess or hole may be adopted.

A ball lc'of, say, onemillimetre diameter" is fixed to the lower end of a holdert' which is attached to the lower face of the upper cross bar m of the stirrup and a horizontal table it tosupport the specimen to be tested is carried at a convenient height by the vertical columns.

When a test is to be made with the apparatus the specimen is placed upon the table a beneath the hardened steel ball 70' and the stirrup is lowered until the ball makes contact withthe specimen so that the stirrup is entirely freed from the suspending and lowering mechanism and the applied load. pressing the ball into the specimen and equal to the weight of the stirrup together with the weight which it carries is suspended freely on the ball.

' After the test the ball is raised from the specimen by reversing the lowering mechanism and the impression made is measured by any suitable means.

During the application of the load and during the measurement of the size of the impression-the object under test may be supported by any suitable means. Two of the convenient means for supporting hollow objects or hollow portions of objects of cylindrical interior form are illustrated by way of example in Figures 3 and 4 in which mandrils '0 of hard steel or other hard material and of circular section are shown supported respectively at the ends byV blocks and in the middle by a carrier of strong and rigid construction. i

It will be understood, however, that the form of supporting device for the specimen may be varied to suit the nature and form of the specimen and we may also vary the means adopted for freely supporting the load upon the ball depending upon any particular practical requirements that may have to be fulfilled.

Having now described our invention what we claim as new and desire to secure by Letters fatent is 1. Apparatus for testing the hardness of materials comprising a support for the specimen to be tested, ahardened steel ball arranged above said support, a stirrup carrying said hardened steel ball and adapted to carry a known weight, and means for lowering said stirrup so that said ball is pressed into contact with said specimen under said known load.

2. Apparatus for testing the hardness of materials comprising a support for the specimen to be tested, a hardened steel ball arranged above said support, a stirrup carrying said hardened steel ball and adapted to carry a known weight, and a hand wheel and screw for lowering said stirrup so that said ball is pressed into contact with said specimen under said known load.

3. Apparatus for testing the hardness of materials comprising a support for the specimen to be tested, ahardened steel ball arranged above said support, a stirrup carrying said. hardened steel ball and adapted to carry a known weight, a hand wheel and screw for lowering said stirrup so that said ball is pressed into contact with said specimen under said known load and means .for preventing rotation of said stirrup.

4. Apparatus for testing the hardness of materials comprising a support for the specimen to be tested, a hardened steel ball arranged above said support, a stirrup carrying said hardened steel ball and adapted to carry a known weight, a hand wheel and screw for lowering said stirrup so that said ball is pressed into contact with said specimen under said known load and means for preventing oscillation of said stirrup.

5. Apparatus for testing the hardness of materials comprising a support for the specimen to be tested, a hardened steel ball arranged above said support, a stirrup carrysaid hardened steel ball and adapted to carry a known weight, a hand wheel and screw for lowering said stirrup so that said ball. is pressed into contact with said specimen under said known load and three triangularly spaced balls from which the said stirrup is suspended.

In testimony whereof we have signed our names to this specification.

HAROLD MOORE. RICHARD MATHER. 

